Realms, also known as dimensions, planes, worlds, and universes, are isolated pockets of existence within the multiverse. Each universe exists within an empty region known as The Void, and each universe is separated by a variety of barriers, the most universal of which is the Abyss. It appears that worlds such as Gielinor and Zanaris are separated by space (as shown in the Origins of Gielinor video) and the Abyss is merely used to travel quickly between them.

Although realms are typically physically separate from each other, various realms have been connected via a number of means, both naturally occurring and artificially devised.

Another possible binding realm may be the Void. The Void is the separation of all the dimensions. The Void is nothing but empty white coloured space. The Void can be seen on the edges of the screen when in the Spirit Realm and is briefly visited during the Summer's End quest.

Runecrafting altars (located within pocket dimensions created by the magical energies of the runestones and altars)

Runecrafting Guild ("within a strange plane parallel to RuneScape", more commonly known as the Runespan. The Runecrafting Guild was created within the Runespan by the magic of the Runecrafting Guild Wizards)

Realm of the Grim Reaper (visited by all players upon death for the first time in Gielinor; where some of the Halloween Holiday Events take place, in the Reaper's very house; possibly the Grim Underworld, though no connection between the Reaper and the demons has yet been established)

Home plane of the dark beasts (described as a "shadowy dimension" and where the potent dark bow came from when the bow was released; the Examine text of both reveals that they have come from a "darker dimension")

Dimension of the Culinaromancer (visited once in the final sub-quest for Recipe for Disaster; blocks Prayer to the Gielinor deities, prevents you from calling upon creatures from the Spirit Plane through Summoning, and forces your gravestone to appear outside portal instead of within dimension upon death)

Realm of Agrith-Naar (possibly part of the Infernal Dimensions; where Guthix banished him to after the God Wars, before he bypassed his Edicts somehow, apparently by causing natural disasters on Gielinor)

It should be noted that the Rune essence mine, though secluded from the rest of RuneScape and accessible only through a certain teleportation spell, is nevertheless a part of Gielinor (unlike the Runecrafting altars or Runecrafting Guild), located in the ice fields to the north.